Almost two years ago, Tesla Motors Inc. and SpaceX Chief Executive Elon Musk unveiled a curious plan: a high-speed transportation system that would shoot passengers and freight between Los Angeles and San Francisco in a vacuum tube at speeds of up to 760 mph.

Musk called it the Hyperloop, released his 58-page “alpha” design as an open-source document and left it at that. On Monday, the billionaire known for big ideas pushed one of his companies back into the forefront of the conversation.

SpaceX, short for Space Exploration Technologies Corp., said it is launching a competition to build and design pods for the Hyperloop. Teams of university students and other independent engineering groups will sign up in September, submit final designs in December and then present their ideas in person in January to a panel of university professors and engineers from SpaceX and Tesla Motors, according to documents obtained by The Times.

A year from now, the teams and their pods will face off on a 1-mile test track to be constructed near SpaceX headquarters in Hawthorne. The company would also probably construct a demonstration pod not eligible to win. No people will ride in any pod during the event.

Though it is initiating the competition, SpaceX was clear about its involvement with the Hyperloop.

“While we are not developing a commercial Hyperloop ourselves, we are interested in helping to accelerate development of a functional Hyperloop prototype,” the company said on its competition website.http://www.spacex.com/hyperloop

In the last several months, a handful of start-ups not affiliated with SpaceX or Elon Musk have started working on the project, including Hyperloop Technologies Inc., which has leased warehouse space in downtown Los Angeles.

Ashlee Vance, author of a biography titled “Elon Musk: Tesla, SpaceX and the Quest for a Fantastic Future,” said the competition didn’t necessarily indicate Musk’s intent to join the Hyperloop project.

“To me, it’s still more of a thought experiment for Elon,” he said. “I would be shocked with everything on his plate that he would be the guy to commercialize it.”

A small number of Tesla Model S owners will have their cars updated for a test of hands-free driving by the end of the month, Elon Musk, chief executive of the electric car company, said at Tesla’s annual shareholders meeting Tuesday.

Speaking at a standing-room-only meeting at the Computer History...

A small number of Tesla Model S owners will have their cars updated for a test of hands-free driving by the end of the month, Elon Musk, chief executive of the electric car company, said at Tesla’s annual shareholders meeting Tuesday.

Speaking at a standing-room-only meeting at the Computer History...

(Jerry Hirsch)

In unveiling his Hyperloop design in August 2013, Musk said the idea stemmed from his disappointment with the California bullet train proposal. More details of the competition will be released in August, according to the documents.

At least one school has already signed on to the project.

Texas A&M University will host the January design event, where teams will get feedback from a panel and companies can connect with teams they want to sponsor — similar to other design competitions. School faculty probably will be involved as student team advisors, Texas A&M spokeswoman Magda Lagoudas said.

Geoff Spedding, a USC professor of aerospace and mechanical engineering, said he already got an email Monday morning from a student interested in participating.

“It’s fun to think about,” Spedding said. “You don’t get anywhere unless you take a few risks.”

He said teams will have to keep passenger comfort in mind, such as spacing people far enough apart, as well as the engineering challenges of designing for the Hyperloop.

But even with the technological difficulties, the Hyperloop still faces concerns about cost. In the August 2013 announcement, Musk said the transportation system could be constructed for $6 billion, a figure several analysts thought was too low.

“I just don’t see how it can compete economically with the airlines and the high-speed rail, or the automobile at the other end of the spectrum,” said Lou Thompson, a transportation consultant. “In this sense, the technology is a very small part of the question. The real question is the cost to construct and operate.”